Stereo Chemistry Flashcards
What is an isomer?
Molecules that have the same molecular formula but different structural formulae.
When do stereoisomers occur?
When the spatial arrangement of the atoms is different in each isomer by the order of bonding is the same.
When do geometric isomers occur?
When there is restricted rotation around a carbon-carbon double bond or a carbon-carbon single bond in a cyclic compound.
What can you tell if an isomer has cis- as the prefix?
That the substituent groups are on the same side.
What can you tell if an isomer has trans- as the prefix?
The substituent groups are on different sides of the bond.
Which type of isomer has differences in physical properties such as melting and boiling points?
Geometric isomers
When can isomers have differences in chemical properties?
When they are geometric or in a chiral environment.
(such as a biological system)
When do optical isomers occur?
In compounds in which four different groups are arranged tetrahedrally around a central carbon atom.
Which type of isomer is asymmetric?
Optical isomers
Which type of isomer is
non-superimposable mirror images of each other?
Optical isomers
What can an optical isomer also be described as?
An enantiomer
Which physical properties differ on optical isomers?
Other than their effect on
plane-polarised light they are identical.
What type of molecules rotate plane-polarised light by the same amount but in opposite directions?
Optical isomers
Why are optical isomers optically inactive when mixed in even amounts?
As their rotational effect of the plane-polarised light cancels out.
What is a racemic mixture?
When optical isomers are mixed in even amounts.
